Insertional Torque in Cervical Vertebrae Lateral Mass Screw Fixation: Magerl Technique Versus Roy-Camille Technique

STUDY DESIGN

This is a prospective multicenter comparison study.

OBJECTIVE

To measure the insertional torque (IT) for cervical vertebra lateral mass screw (LMS) fixation using the Magerl and Roy-Camille methods, at the discretion of the surgeon.

SUMMARY OF BACKGROUND DATA

Current fixation methods for patients with preoperative cervical spine instability use LMSs; however, few studies have closely examined intraoperative IT. Patients' bone quality was not measured.

METHODS

A total of 637 posterior cervical multiaxial screws were inserted for LMS (C3-C6) (Magerl technique, 423; Roy-Camille technique, 214) in 107 cases. Patients' mean age was 66 years. Patients treated with the Magerl method were divided into 2 groups, with the men in the MM group and the women in the MF group. Similarly, patients treated with the Roy-Camille method were divided into 2 groups, with the men in the RM group and the women in the RF group. The contralateral cortex was penetrated, and the IT at cerclage was measured at the last time.

RESULTS

IT of the lateral mass screw was 53.8±22.4, 45.4±21, 45.5±16.9, and 34±16.4 cN.m in the MM group (258), MF group (165), RM group (163), and RF group (51), respectively. The MM group had a significantly higher IT than the other 3 groups, and the RM group had a significantly higher IT than the RF group. When the correlation between screw length and IT was evaluated, IT was significantly (P<0.05) higher with a longer screw by the Magerl method.

CONCLUSIONS

The IT was higher with the Magerl method with a longer screw. Screw length and IT were not correlated with the Roy-Camille method; furthermore, the Roy-Camille method went through bilateral cortical bone perpendicularly, so that IT was determined by the fixation power in the cortical part of the bone, which was not thought to be affected by screw length.

LEVEL OF EVIDENCE

Level III.

Frequency of severe neutropenia occurring as an adverse events of gemcitabine plus cisplatin chemotherapy in patients with recurrent biliary tract cancer compared to those with unresectable biliary tract cancer

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Background: In patients (pts) with biliary tract cancer (BTC), relapse occurs at a high frequency even after curative resection. It remains unclear whether in pts with postoperative recurrence receiving chemotherapy, the surgery exerts any influence on the risk of development of toxicities. The aim of this study was to compare the outcomes and incidences of adverse events between recurrent BTC (rBTC) pts and unresectable BTC (uBTC) pts receiving gemcitabine plus cisplatin chemotherapy (GC). Methods: Data of pts with rBTC or uBTC receiving GC as the first-line chemotherapy were analyzed. The GC regimen consisted of gemcitabine 1000 mg/m2 plus cisplatin 25 mg/m2on days 1 and 8, administered every 3 weeks. All adverse events occurring during the first 180 days of GC were evaluated according to CTCAE, version 4.0. Results: A total of 151 pts, including 55 pts with rBTC and 96 pts with uBTC, were enrolled. In regard to the baseline characteristics, no significant differences between the rBTC and uBTC groups were found in the gender distribution [male: 69% vs. 57%], age [median: 68 vs. 68], or ECOG performance status (PS) [PS0: 67%vs. 55%]. The distribution of the primary tumor site (intrahepatic bile duct [27% vs. 33%] / extrahepatic bile duct [45% vs. 20%] / gallbladder [20% vs. 44%] / ampulla [7% vs. 3%]) was unbalanced between the two groups ( p < 0.01). The overall survival (OS) was significantly longer in the rBTC group than that in the uBTC group [median 15.8 months vs. 10.0 months, p = 0.02], however, there was no significant difference in the progression-free survival [median 6.8 months vs. 5.8 months] between the two groups. Grade 3-4 neutropenia was more frequent in the rBTC group [69%] as compared to that in the uBTC group [44%, p < 0.01], whereas Grade 3-4 cholangitis was significantly less frequent in the rBTC [5%] group than that in the uBTC group [21%, p = 0.02]. Conclusions: The incidence of Grade 3-4 neutropenia developing during GC was significantly higher in the rBTC group as compared to that in the uBTC group.

The effect of duloxetine on chemotherapy-induced peripheral neuropathy in advanced pancreatic cancer patients receiving gemcitabine plus nab-paclitaxel treatment

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Background: Recently, gemcitabine plus nab-paclitaxel (GN) has come to be used frequently as the first-line chemotherapy for advanced pancreatic cancer. It has been reported that chemotherapy-induced peripheral neuropathy (CIPN) associated with nab-paclitaxel (nab-PTX) may impair the quality of life of the patients, and may, moreover, necessitate dose reduction or early cessation of the chemotherapy, thereby potentially impacting patient survival. However, there are no established treatments against CIPN. Several reports have suggested that duloxetine, which has been proved to be highly effective in managing diabetic peripheral neuropathy, is also effective against CIPN induced by platinum agents and taxanes. The aim of this study was to examine the frequency of nab-PTX related CIPN, its various influences, and the efficacy of duloxetine in the management of CIPN. Methods: Data of 121 pancreatic cancer patients who received GN as first chemotherapy between December 2014 and December 2015 at the National Cancer Center Hospital East, Japan, were analyzed retrospectively. Results: The frequency of CIPN of any grade was 60.3% (73 patients) and that of CIPN of grade ≥ 2 was 21.5% (26 patients). Among the patients who showed CIPN, 34 patients received 20-60 mg of duloxetine once daily, and the remaining patients never received it (no duloxetine group). 18 patients were on duloxetine for more than four weeks (the duloxetine group). 8 patients discontinued duloxetine in less than four weeks because of its side effects, such as, nausea, and somnolence. In the duloxetine group, CIPN was improved in 4 patients, and remained non-progressive in 12 patients. The relative dose intensity (RDI) of nab-PTX since the emergence of CIPN in the duloxetine group was higher than that in the no duloxetine group (63.2 % vs. 48.2 %, p = 0.0046). Conclusions: The frequency of nab-PTX related CIPN at our hospital was almost similar to that of previous reports. The results of this study suggest the possibility that duloxetine not only improves nab-PTX-related CIPN, but delays its progression. Therefore, it might contribute to continuing GN with a high RDI for longer periods of time.

Inhibitory effect of fentanyl citrate on the release of endothlin-1 induced by bradykinin in melanoma cells

BACKGROUND

Our previous study showed that the μ-opioid receptor agonist fentanyl citrate inhibits endothelin-1-and bradykinin-mediated pain responses in mice orthotopically inoculated with melanoma cells. We also demonstrated that bradykinin induces endothelin-1 secretion in melanoma cells. However, the analgesic mechanisms of fentanyl citrate remain unclear. Thus, the present study was conducted to determine whether fentanyl citrate affects bradykinin-induced endothelin-1 secretion in B16-BL6 melanoma cells.

METHODS

The amount of endothelin-1 in the culture medium was measured using an enzyme immunoassay. The expression of endothelin-1, kinin B₂ receptors, and μ-opioid receptors in B16-BL/6 melanoma cells was determined using immunocytochemistry.

RESULTS

Fentanyl citrate inhibited bradykinin-induced endothelin-1 secretion. The inhibitory effect of fentanyl citrate on the secretion of endothelin-1 was attenuated by the μ-opioid receptor antagonist naloxone methiodide. The immunoreactivities of endothelin-1, kinin B₂ receptors, and μ-opioid receptors in B16-BL6 melanoma cells were observed.

CONCLUSION

These results suggest that fentanyl citrate regulates bradykinin-induced endothelin-1 secretion through μ-opioid receptors in melanoma cells.

Gamma-irradiated quiescent cells repair directly induced double-strand breaks but accumulate persistent double-strand breaks during subsequent DNA replication

H2AX is expressed at very low levels in quiescent normal cells in vivo and in vitro. Such cells repair DNA double-strand breaks (DSBs) induced by γ-irradiation through a transient stabilization of H2AX. However, the resultant cells accumulate small numbers of irreparable (or persistent) DSBs via an unknown mechanism. We found that quiescent cells that had repaired DSBs directly induced by γ-rays were prone to accumulate DSBs during the subsequent DNA replication. Unlike directly induced DSBs, secondary DSBs were not efficiently repaired, although Rad51 and 53BP1 were recruited to these sites. H2AX was dramatically stabilized in response to DSBs directly caused by γ-rays, enabling γH2AX foci formation and DSB repair, whereas H2AX was barely stabilized in response to secondary DSBs, in which γH2AX foci were small and DSBs were not efficiently repaired. Our results show a pathway that leads to the persistent DSB formation after γ-irradiation.

Assessment of maximal insertional torque of cervical and thoracic screws during posterior spinal surgery

STUDY DESIGN

Multicenter intraoperative biomechanical analysis.

PURPOSE

This study aimed to assess the maximal insertional torque (MIT) of lateral mass screw (LMS) and pedicle screw (PS) in the cervical or thoracic vertebrae during surgery.

METHODS

During posterior spinal fusion, cervical or thoracic multi-axial screws were placed at different cervical or thoracic levels and the MIT was recorded for each screw revolution using an analogue torque wrench. Screw number was as follows: 11 PS at C7, 134 LMS (C3-6) (Magerl technique, 70; Roy-Camille technique, 64), and 33 PS in the thoracic region.

RESULTS

Average MIT values (cNm) were as follows: for PS (diameter: 3.5 mm) at C7, 45.3 ± 21.9 in men and 60.0 ± 20.1 in women (p=0.28); for Magerl screws, 69.0 ± 20.5 in men and 58.6 ± 15.7 in women (p=0.13); and for Roy-Camille screws, 51.0 ± 17.9 in men and 42.4 ± 15.9 in women (p=0.52). The average MIT for Magerl screws was significantly higher than that for Roy-Camille screws in men and women (both p<0.01).

CONCLUSIONS

Intraoperative insertional torque could be a good indicator to evaluate the purchase and help guide decisions on screw type and insertion technique. Further postoperative assessments with sequential X-rays are needed to reveal the significance of MIT during posterior spinal fusion.

Development and evaluation of a collection apparatus for recoil products for study of the deexcitation process of (235m)U

The nucleus (235m)U is an isomer with extremely low excitation energy (76.8 eV) and decays dominantly through the internal conversion (IC) process. Because outer-shell electrons are involved in the IC process, the decay constant of (235m)U depends on its chemical environment. We plan to study the deexcitation process of (235m)U by measuring the energy spectra of IC electrons in addition to the decay constants for various chemical forms. In this paper, the preparation method of (235m)U samples from (239)Pu by using alpha-recoil energy is reported. A Collection Apparatus for Recoil Products was fabricated, and then collection efficiencies under various conditions were determined by collecting (224)Ra recoiling out of (228)Th electrodeposited and precipitated sources. The pressure in the apparatus (vacuum or 1 atm of N2 gas) affected the variations of the collection efficiencies depending on the negative voltage applied to the collector. The maximum values of the collection efficiencies were mainly affected by the thickness of the (228)Th sources. From these results, the suitable conditions of the (239)Pu sources for preparation of (235m)U were determined. In addition, dissolution efficiencies were determined by washing collected (224)Ra with solutions. When (224)Ra was collected in 1 atm of N2 gas and dissolved with polar solutions such as water, the dissolution efficiencies were nearly 100%. The method of rapid dissolution of recoil products would be applicable to rapid preparation of short-lived (235m)U samples for various chemical forms.

Chromosome Synapsis Alleviates Mek1-Dependent Suppression of Meiotic DNA Repair

Faithful meiotic chromosome segregation and fertility require meiotic recombination between homologous chromosomes rather than the equally available sister chromatid, a bias that in Saccharomyces cerevisiae depends on the meiotic kinase, Mek1. Mek1 is thought to mediate repair template bias by specifically suppressing sister-directed repair. Instead, we found that when Mek1 persists on closely paired (synapsed) homologues, DNA repair is severely delayed, suggesting that Mek1 suppresses any proximal repair template. Accordingly, Mek1 is excluded from synapsed homologues in wild-type cells. Exclusion requires the AAA⁺-ATPase Pch2 and is directly coupled to synaptonemal complex assembly. Stage-specific depletion experiments further demonstrate that DNA repair in the context of synapsed homologues requires Rad54, a repair factor inhibited by Mek1. These data indicate that the sister template is distinguished from the homologue primarily by its closer proximity to inhibitory Mek1 activity. We propose that once pairing or synapsis juxtaposes homologues, exclusion of Mek1 is necessary to avoid suppression of all templates and accelerate repair progression.

Experiments in yeast indicate that one function of the synaptonemal complex is to disable chromosome-bound Mek1 kinase, thereby promoting DNA repair on fully paired meiotic chromosomes and helping to favor recombination between homologues over sister chromatids.

Chromosome segregation errors during meiosis may cause infertility, fetal loss, or birth defects. To avoid meiotic chromosome segregation errors, recombination-mediated linkages are established between previously unattached homologous chromosomes. Such recombination events initiate with breaks in the DNA, but how these breaks are preferentially repaired using the distal homologous chromosome, rather than the physically more proximal sister chromatid of similar sequence, is not well understood. Meiotic repair-template bias in the budding yeast depends on the function of Mek1, a meiosis-specific protein kinase. Previous models suggested that Mek1 activity creates repair-template bias by suppressing repair with the sister chromatid. We found that Mek1 localizes on meiotic chromosomes until the homologues pair and closely align. Removal of Mek1 requires the assembly of a conserved zipper-like structure between meiotic chromosomes, known as the synaptonemal complex. DNA break repair is delayed in mutants in which Mek1 persists on closely aligned homologues. These findings suggest that persistent Mek1 activity can suppress repair from all templates, and that one function of the synaptonemal complex is to remove this activity from chromosomes. Our findings build on previous models to propose that Mek1 activity creates a local zone of repair suppression that is normally avoided by the spatially distant homologous chromosome to promote repair-template bias.

Cytochrome P450 CYP71BE5 in grapevine (Vitis vinifera) catalyzes the formation of the spicy aroma compound (-)-rotundone

(-)-Rotundone is a potent odorant molecule with a characteristic spicy aroma existing in various plants including grapevines (Vitis vinifera). It is considered to be a significant compound in wines and grapes because of its low sensory threshold and aroma properties. (-)-Rotundone was first identified in red wine made from the grape cultivar Syrah and here we report the identification of VvSTO2 as a α-guaiene 2-oxidase which can transform α-guaiene to (-)-rotundone in the grape cultivar Syrah. It is a cytochrome P450 (CYP) enzyme belonging to the CYP 71BE subfamily, which overlaps with the very large CYP71D family and, to the best of our knowledge, this is the first functional characterization of an enzyme from this family. VvSTO2 was expressed at a higher level in the Syrah grape exocarp (skin) in accord with the localization of (-)-rotundone accumulation in grape berries. α-Guaiene was also detected in the Syrah grape exocarp at an extremely high concentration. These findings suggest that (-)-rotundone accumulation is regulated by the VvSTO2 expression along with the availability of α-guaiene as a precursor. VvSTO2 expression during grape maturation was considerably higher in Syrah grape exocarp compared to Merlot grape exocarp, consistent with the patterns of α-guaiene and (-)-rotundone accumulation. On the basis of these findings, we propose that VvSTO2 may be a key enzyme in the biosynthesis of (-)-rotundone in grapevines by acting as a α-guaiene 2-oxidase.

Risk factors of chemotherapy-induced nausea and vomiting in patients with advanced pancreatic cancer receiving modified FOLFIRINOX

344

Background: Modified FOLFIRINOX (mFFX) has been reported to be a high incidence of chemotherapy-induced nausea and vomiting (CINV). However, CINV is difficult to adequately control in patients receiving treatment with mFFX. The aim of this study is to evaluate the incidence of delayed CINV and to identify as risk factors for CINV in patients receiving treatment with mFFX. Methods: The study subjects were patients with advanced pancreatic cancer treated with mFFX from December 2013 to June 2015 at National Cancer Center Hospital East. The mFFX regimen consisted of oxaliplatin 85 mg/m2, irinotecan 150 mg/m2, l-leucovorin 200 mg/m2 and a 46-h continuous infusion of fluorouracil 2400 mg/m2. The antiemetic prophylaxis consisted of aprepitant (125 mg on day1 and 80 mg on day 2-3), palonosetron (0.75 mg on day1) and dexamethasone (12 mg on day1 and 8 mg on day 2-3). All adverse events, including nausea and vomiting were graded according to the Common Toxicity Criteria for Adverse Events (CTCAE version 4.0). Results: A total of 115 patients were enrolled in this study. The incidence rates of nausea and vomiting of any grade during the first treatment cycle were 45.2% and 5.2%, respectively. Grade 2-3 of nausea and vomiting were observed in 13.9% and 0.9% of the patients, respectively. Any grade of CINV occurred frequently during days 4 to 7 for the first treatment cycle. Univariate and multivariate analyses identified female and younger age ( < 50 years) as significant independent factors associated with the incidence of any grade of CINV on days 4 to 7 for the first treatment cycle (Odds ratio [OR], 7.44; 95%CI, 2.21 to 25.1; p = 0.001; OR, 4.57; 95% CI, 1.04 to 20.1; p = 0.044). Conclusions: The risk factors of delayed CINV for the first treatment cycle were identified as female and younger age in patients treated with mFFX. Therefore, in patients with these risk factors, additional dexamethasone should be considered as an antiemetic treatment on day 4-5.

Rad61/Wpl1 (Wapl), a cohesin regulator, controls chromosome compaction during meiosis

Meiosis-specific cohesin, required for the linking of the sister chromatids, plays a critical role in various chromosomal events during meiotic prophase I, such as chromosome morphogenesis and dynamics, as well as recombination. Rad61/Wpl1 (Wapl in other organisms) negatively regulates cohesin functions. In this study, we show that meiotic chromosome axes are shortened in the budding yeast rad61/wpl1 mutant, suggesting that Rad61/Wpl1 negatively regulates chromosome axis compaction. Rad61/Wpl1 is required for efficient resolution of telomere clustering during meiosis I, indicating a positive effect of Rad61/Wpl1 on the cohesin function required for telomere dynamics. Additionally, we demonstrate distinct activities of Rad61/Wpl1 during the meiotic recombination, including its effects on the efficient processing of intermediates. Thus, Rad61/Wpl1 both positively and negatively regulates various cohesin-mediated chromosomal processes during meiosis.

Self-assessment of Rheumatoid Arthritis Disease Activity Using a Smartphone Application. Development and 3-month Feasibility Study

INTRODUCTION

This article is part of the Focus Theme of Methods of Information in Medicine on "Methodologies, Models and Algorithms for Patients Rehabilitation".

BACKGROUND

Rheumatoid arthritis (RA) is a progressive inflammatory disease that causes damage to multiple joints, decline in functional status, and premature mortality. Thus, effective and frequent objective assessments are necessary. Then, we developed a self-assessment system for RA patients based on a smartphone application.

OBJECTIVE

The purpose of this study was to investigate the feasibility of a self-assessment system for RA patients using a smartphone application.

METHODS

We measured daily disease activity in nine RA patients who used the smartphone application for a period of three months. A disease activity score (DAS28) predictive model was used and feedback comments relating to disease activity were shown to patients via the smartphone application each day. To assess participants' RA disease activity, the DAS28 based on the C-reactive protein level was measured by a rheumatologist during monthly clinical visits.

RESULTS

The disease activity measured by the application correlated well with the patients' actual disease activity during the 3-month period, as assessed by clinical examination. Furthermore, most participants gave favourable responses to a questionnaire administered at the end of the 3-month period containing questions relating to the ease of use and usefulness of the system.

CONCLUSIONS

The results of this feasibility study indicated that the DAS28 predictive model can longitudinally predict DAS28 and may be an acceptable and useful tool for assessment of RA disease activity for both patients and healthcare providers.

Comparing immunocompetent and immunodeficient mice as animal models for bone tissue engineering

OBJECTIVES

To understand the differences and similarities between immunocompetent and immunodeficient mice as ectopic transplantation animal models for bone tissue engineering.

MATERIALS AND METHODS

Osteogenic cells from mouse leg bones were cultured, seeded on β-TCP granules, and transplanted onto the backs of either immunocompetent or immunodeficient nude mice. At 1, 2, 4, and 8 weeks postoperatively, samples were harvested and evaluated by hematoxylin-eosin staining, tartrate-resistant acid phosphatase (TRAP) staining, and immunohistochemical staining and quantitative PCR.

RESULTS

In immunocompetent mice, inflammatory cell infiltration was evident at 1 week postoperatively and relatively higher expression of TNF-α and IL-4 was observed. In immunodeficient mice, new bone area and the number of TRAP-positive cells were larger at 4 weeks than in immunocompetent mice. The volume of new bone area in immunodeficient mice was reduced by 8 weeks.

CONCLUSIONS

Bone regeneration was feasible in immunocompetent mice. However, some differences were observed between immunocompetent and immunodeficient mice in the bone regeneration process possibly due to different cytokine expression, which should be considered when utilizing in vivo animal models.

DNA damage response clamp 9-1-1 promotes assembly of ZMM proteins for formation of crossovers and synaptonemal complex

Formation of crossovers between homologous chromosomes during meiosis is positively regulated by the ZMM proteins (also known as SIC proteins). DNA damage checkpoint proteins also promote efficient formation of interhomolog crossovers. Here, we examined, in budding yeast, the meiotic role of the heterotrimeric DNA damage response clamp composed of Rad17, Ddc1 and Mec3 (known as '9-1-1' in other organisms) and a component of the clamp loader, Rad24 (known as Rad17 in other organisms). Cytological analysis indicated that the 9-1-1 clamp and its loader are not required for the chromosomal loading of RecA homologs Rad51 or Dmc1, but are necessary for the efficient loading of ZMM proteins. Interestingly, the loading of ZMM proteins onto meiotic chromosomes was independent of the checkpoint kinase Mec1 (the homolog of ATR) as well as Rad51. Furthermore, the ZMM member Zip3 (also known as Cst9) bound to the 9-1-1 complex in a cell-free system. These data suggest that, in addition to promoting interhomolog bias mediated by Rad51-Dmc1, the 9-1-1 clamp promotes crossover formation through a specific role in the assembly of ZMM proteins. Thus, the 9-1-1 complex functions to promote two crucial meiotic recombination processes, the regulation of interhomolog recombination and crossover formation mediated by ZMM.

A Novel Percutaneous Guide Wire (S-Wire) for Percutaneous Pedicle Screw Insertion: Its Development, Efficacy, and Safety

PURPOSE

Minimally invasive spine stabilization (MISt) procedures, including MIS-transforaminal lumbar interbody fusion (MIS-TLIF), rely on precise placement of percutaneous pedicle screws (PPS). Serious intraoperative complications associated with PPS placement include great vessel and bowel injuries due to the guide-wire's anterior migration and penetration through the anterior aspect of the vertebral body. To address this issue, we developed a novel percutaneous guide wire (S-wire) and compared the biomechanical characteristics of S-wire and conventional wire in cadaveric spines, and to evaluate the S-wire's efficacy and safety in a clinical trial.

METHODS

The S-wire is hollow, with braided wires extending at one tip. We compared the push-out and penetration forces of the S-wire and conventional wire in fresh cadaveric lumbar spines, from L1 to L5.

RESULTS

Push-out forces caused the braided tip of the S-wire to bend or spread, and thus to resist anterior migration. The mean push-out forces for the S-wire and conventional wire were 15.5 ± 1.9 and 5.7 ± 0.8 N, respectively (P < .0001); the mean penetration forces were 69.1 ± 4.2 and 37.1± 4.8 N, respectively (P < .0005). There was no wire breakage or anterior-wall penetration in a clinical trial of 922 S-wires; interestingly, the pull-out force increased in 780 (84.6%) S-wires after placement.

CONCLUSIONS

The mean push-out and penetration forces for the S-wire were approximately 3 and 2 times greater than those of conventional wire, respectively. The S-wire effectively prevented guide-wire anterior migration and penetration of the anterior vertebral-body wall. The S-wire device should effectively improve the safety of MISt procedures, including MIS-TLIF and percutaneous kyphoplasty in selected patient with osteoporosis.

Double-strand break repair-adox: Restoration of suppressed double-strand break repair during mitosis induces genomic instability

Double-strand breaks (DSBs) are one of the severest types of DNA damage. Unrepaired DSBs easily induce cell death and chromosome aberrations. To maintain genomic stability, cells have checkpoint and DSB repair systems to respond to DNA damage throughout most of the cell cycle. The failure of this process often results in apoptosis or genomic instability, such as aneuploidy, deletion, or translocation. Therefore, DSB repair is essential for maintenance of genomic stability. During mitosis, however, cells seem to suppress the DNA damage response and proceed to the next G₁ phase, even if there are unrepaired DSBs. The biological significance of this suppression is not known. In this review, we summarize recent studies of mitotic DSB repair and discuss the mechanisms of suppression of DSB repair during mitosis. DSB repair, which maintains genomic integrity in other phases of the cell cycle, is rather toxic to cells during mitosis, often resulting in chromosome missegregation and aberration. Cells have multiple safeguards to prevent genomic instability during mitosis: inhibition of 53BP1 or BRCA1 localization to DSB sites, which is important to promote non-homologous end joining or homologous recombination, respectively, and also modulation of the non-homologous end joining core complex to inhibit DSB repair. We discuss how DSBs during mitosis are toxic and the multiple safeguard systems that suppress genomic instability.

Measurements of the neutron activation cross sections for Bi and Co at 386 MeV

Neutron activation cross sections for Bi and Co at 386 MeV were measured by activation method. A quasi-monoenergetic neutron beam was produced using the (7)Li(p,n) reaction. The energy spectrum of these neutrons has a high-energy peak (386 MeV) and a low-energy tail. Two neutron beams, 0° and 25° from the proton beam axis, were used for sample irradiation, enabling a correction for the contribution of the low-energy neutrons. The neutron-induced activation cross sections were estimated by subtracting the reaction rates of irradiated samples for 25° irradiation from those of 0° irradiation. The measured cross sections were compared with the findings of other studies, evaluated in relation to nuclear data files and the calculated data by Particle and Heavy Ion Transport code System code.